From the blog

Hidden in the Wi-Fi settings on my laptop is a list of all the Wi-Fi networks I’ve ever connected to. Quickly scrolling through, you can start to get a sense of how many different public Wi-Fi providers there are. There’s names like BT, The Cloud and Boingo that stick out. Each will have their own terms and conditions, likely hastily agreed to while I’ve sat in the various places that public Wi-Fi is available in London.